Note: Descriptions are shown in the official language in which they were submitted.
HOECHST AKTIENGESELLSCHAFT HOE 91/F 008 Dr.KI/je
Copolymers of diallylaminoalkylenephosphonates and
unsaturated carboxylic acids
In the extraction of oil, water and gas from underground
forma~ions, scale formation, i.~e. the precipitation of
sparingly soluble salts of the alkaline earth metals, may
occur due to mixing of different saline waters in the
well hole, variations in temperature and pressure and
similar circumstances during extraction. Scale formation
can lead, inter alia, to blocked well holes, delivery
pipes and pipelines as well as to seized pumps and valves
and can cause considerable repair costs.
To prevent scale formation, on the one hand high mole-
cular weight polycarboxylic acids (preferably to counter-
act alkaline earth metal sulfate) and on the other handlow molecular weight polyelectrolytes, such as amino-
methylenephosphonic acids (preferably to counteract
alkaline earth metal carbonate3 are added to saline
waters in sub6toichiometric amounts in the range from 1
to 100 ppm. It is assumed that for this so-called
"threshold effect", the polyelectrolyte is absorbed onto
the surfaces of the crystals and in this way interferes
with or suppresses further crystal growth.
Aminomethylenephosphonic acids (for axample Dequest,
Monsanto) and other low molecular wei~ht polyelectro-
lytes, such as, for example, EDT~ and triphosphates, also
have a broad practical application in bleaching washing
because of their good bonding capacity for calcium and
heavy metals. The heavy metals present reduce the stoxage
stability of detergent formulations and damage the fibars
during bleaching, and they must therefore as far as
possible be removed fcr bleaching washing. High molecular
weight polycarboxylic acids lRagnetti; Tenside, Surfac-
tants, Detergents 1989, 26, 30) are similarly of great
importance as co-builders in phosphate-free and -reduced
', ~
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-- 2 --
detergents. They probably transport water-soluble metal
ions, in particular calcium ions, from the aqueous
detergent liquor into the water-~insoluble zeolites used
as builders here.
The present invention relates to copolymers which combine
the properties of these two classes of substance.
(Co)polymerizable phosphonic acid derivatives are acces-
sible by a Mannich reaction of (di~allylamines with
aldehydes and phosphorous acid (R. Moedritæer, R.R.
Irani, J. Org. Chem. 1966, 31, 1603).
Homopolymers of diallylaminomethylenephosphonic acid can
be employed in flame retardant woven fabrics (JP 76
07,214) and as a complexing reagent for zinc ions (JP
78 19,921). However, like their high molecular wei~ht
copolymers with unsaturated carboxylic acids, they have
no effect as a scale inhibitor in saline waters or as a
builder or cobuilder in detergents. The polyelectrolyte
poly(diallyldimethylammonium chloride) which is acces-
sible in a similar manner is used, inter alia, as a
flocculating agent (C. Wandrey et al.; Wasserwirtschaft
1984, 8, 185).
Copolymers of diallylaminomethylenephosphonic acid and
other unsaturated monomers, such as, for example, acrylic
acid, acrylic acid esters or acrylic acid amides, have
already been described in Japanese Laid-Open Specifica-
tion 50-72,987. The copolymers are prepared by polymer-
ization at temperatures up to 70C. Because of this
relatively low polymerization temperature, these copoly-
mers have a relatively high molecular weight. However,
such products cannot be used as a scale inhibitor.
It has now been found that those copolymers based on
diallylaminomethylenephosphonic acids ale considerably
more active as scale inhibitors if the molecular weiyht
of the copolymers is lower (K values in the range from 10
to 100, intrinsic viscosity measured by the ~bbelohde
.
-
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-- 3 --
method) than that of the copolymers of Japanese Laid-Open
Specification 502,987. This lowering of the molecular
weight is achieved by increalsing the polymeri~ation
temperature and/or addition of a regulator to the poly-
merization system.
The invention thus relates to copolymers having a low
average molecular weight corresponding to an intrinsic
viscosity of 10 to 100 (measured by the Ubbelohde method)
of 0.1-50 mol %, preferably 1-15 mol ~, of at least one
diallylaminomethylenephosphonate of the formula Ia or Ib
(CH2=CH-CH2)2N~(Rl)-CHR2-PO3M-, (Ia)
(CH2=CH-CHz)2N-CHR2-PO3M2 (Ib)
in which R1 is hydrogen, C1- to C22-, preferably C1- to C4-
alkyl, phenyl or C2- to C4-alkenyl, R2 is hydrogen, Cl-to
C4-alkyl or phenyl and M is hydrogen, a cation, such as
Na , X+ or NH4~, Cl- to C4-alkyl or benzyl, and 99.~-50 mol
%, preferably 99-85 mol %, of at least one ethylenically
unsaturated carboxylic acid of the formula II
R3R4C=CR5y (II)
in which R3 is hydrogen or a group of the formula COOM, R4
is hydrogen, phenyl or a group of the formula COOM, Rs is
hydrogen, methyl or a group of the formula COOM or
CH2COOM, Y is a group of the formula COOM, or R4 and R5
together are a C4-alkylene radical, or R4 and Y together
are a group of the formula -C(O)-O-C(O)-, or R5 and Y
together are a group of the fonmula -CH2-C(O)-O-C(O)-,
and M is hydrogen or a cation,
and 0 to 10 mol % of other ethylenically unsaturated
monomers.
Examples which may be mentioned of the monomers of the
formula Ia~Ib are diallylaminomethylenephosphonic acid,
diallylaminoethylenephosphonicacid,diallylaminobenzyli-
, ,~
-
denephosphonic acid and diethyl diallylaminomethylene-
phosphonate, and examples which may be mentioned as
representative of comonomers of the formula II are
acrylic acid, methacrylic aci~d, maleic acid, maleic
anhydride, itaconic acid and cinnamic acid, as well as
lower alkyl esters thereof, such as methyl acryla~e and
methyl methacrylate. According to the invention, however,
other ethylenically unsaturated monomers can also addi-
tionally be employed, such as, for example, vinylsulfonic
acid, vinylphosphonic acid, vinylpyrrolidone, acrylamide
and N- and N,N-substitution products thereof, such as N-
methylacrylamide or 2-acrylamido-2-methylpropanesulfonic
acid, and also allyl compounds of the formula III
Rl'
(CH2=CR6-CH2)"--N l--(Rl )b X' ~III)
I
R' .
in which Rl, R1 and Rl independently of one another have
the meanings given above for Rl or are tha group
CHR2-PO3M2, M is hydrogen, a cation or Cl- to C4-alkyl or
phenyl, R6 is hydrogen or methyl, a is 1 or 2, b is 0 or
1, a+b is 2 and X- is an ~nion of an organic or inorganic
acid, such as Cl-, Br~, HS04- or CH3C00-, in particular
allylamino-bis(methylenephosphonic acid) and allylamino-
benzylidenephosphonic acid. The preferred amount of these
comonomers here is between 0.001 and 10 mol %.
The copolymers according to the invention of diallyl-
aminophosphonates are prepared by polymerizing compounds
of the formula Ia or Ib, which can be contaminated, if
appropriate, with neutralization salts, such as sodium
sulfate or sodium chloride, and compounds of the formula
II and if appropriate other ethylenically unsaturated
compounds in water and~or in water-miscible organic
solvents, preferably at temperatures above 70C, u~ing a
free radical chain initiator, for example ammonium
peroxodisulfate, hydrogen peroxide or tert-butyl
~:
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-- 5 --
hydroperoxide. The compounds of the formula Ia/Ih and
also other comonomers which are added if appropriate (for
example those of the formula III) can be either initYally
introduced in the aqueous solution or added to the
reaction vessel together with the compounds of the
formula II. The total monomer concentration is preferably
1 to 60% by weight, and preferably 10 to 60~ by weight.
If the compounds here are water-in~oluble
diallylaminomethylenephosphonic acids, they can be
converted into their alkali metal or ammonium salts
beforehand. The free radical initiator, if appropriate
dissolved in a suitable solvent, can be added to the
reaction vessel at the same tLme as or after the
compounds of the formulae Ia/Ib and II.
The achievement of a low molecular weight, which is
important for the use according to the invention, can be
influenced favorably by polymerization above 70~ and/or
by the use of lower alcohols (C1-C5) as the solvent and/or
also by addition of 0.001 to 50% by weight of known
regulators, such as thioglycolic acid or dodecanethiol,
to the reaction batch. The % by weight relates to the
monomers. The intrinsic viscosity X (determination by the
~bbelohde method) of the polymer~ is between 10 and 100,
in particular between 10 and 50.
One variant of the process is the polymeri~ation of oil-
soluble diallylaminomethylenephosphonic acid dialkyl
esters with oleophilic comonomers in organic ~olvents
using free radical initiators such as AIBN or organic
peroxides. Subsequent hydrolysis of the ester and anhyd-
ride groups and removal of the organic solvent by distil-
lation gives polymers according to the invention. Suit-
able comonomers here are, inter alia, acrylic acid,
maleic anhydricle and vinyl aceta-te, and preferred sol-
vents are aromatic, aliphatic and also halogenated
hydrocarbons.
Depending on the intended use, the viscous polymer
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solutions are brought to the desired pH with bases,
diluted or spray-dried. The copolymers according to the
invention are attributed the ~eneral formula
T - CH - CH ~ ~ i ~ ;
CH2~ + CH2 ~ LR4 Y J
hardly any crosslinking and Eormation of insoluble
structures consequently occurs.
In saline formation waters, the copolymers according to
the invention lead to effective inhibition both of
alkaline earth metal carbonate deposits and of alkaline
earth metal sulfate deposits. At the same time, they have
an anticorrosion action. They can furthermore be used as
complexing agents for alkaline earth metals and heavy
metals, and because of their outstanding dispersing
action on calcium carbonate, as builders and co-builders
in detergents.
The invention will be illustrated in more detail with the
aid of the following examples.
Examples
The percentage data are to be understood in all cases as
percentages by weight. The water used in the examplss is
deionized. The intrinsic viscosity values R were deter-
mined by the Ubbelohde method.
The pol~merizations were carried out in 1 1 5-necked
flasks with ground glass lids. The flasks are fitted with
an anchor stirrer, thermometer, reflux condenser, gas
inlet tl~be and dxopping funnel. The solutions initially
introduced for the polymerization were flushed wi~h
nitrogen.
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Example 1
Preparation of a copolymer of acrylic acid and 5~ of
diallylaminomethylenephosphonic acid
2.5 g of diallylaminomethylenephosphonic acid are
dissolved in 100 g of water and 20 g of isopropanol and
~he solution i6 heated to 75Cr while passing in a stream
of nitrogen. A catalyst solution consisting of 1.5 g of
(NHd)2S208 in 30 g of water, and 47.5 g of acrylic acid;
are synchronously added dropwise from 2 dropping funnels
at this temperature. When the exothermic reaction phase
has ended, the mixture is subsec~ently stirred at 80C
for 4 hours. The colorless 25% strength polymer solution
has an intrinsic viscosity K of between 20 and 25.
Example 2
Preparation of a copolymer of acrylic acid and 10% of
diallylaminomethylenephosphonic acid
A mixture of 100 g of water and 20 g of isopropanol is
heated to 80C, while passing through a stream of nitro-
gen. A solution of 5 g of diallylaminomethylenephosphonic
acid in 45 g of acrylic acid and a solution of 1.5 g of
(NH4)2S2O8 in 30 g of water are synchronously added
dropwise from 2 dropping funnels. After the mixture has
been subsequently stirred for 4 hours, a 25% strength
polymer solution ha~ing an intrinsic viscosity ~ of
between 15 and 20 is obtained.
Example 3
Preparation of a copolymer of acrylic acid and 10% of
diallylaminomethylenephosphonic acid
5 g of diallylaminomethylenephosphonic acid are dissolved
in 120 g of water and the solution is heated to 80C,
while passing in a stream of nitrogen. A catalyst
solution consisting of 1.5 g of (NH4)2S20~ in 30 g of
water, and a mixture of 45 g of acrylic acid and 4.5 g of
thioglycolic acid, are synchronously added dropwise fr~m
2 dropping funnels at this temperatureO When the exother-
mic reaction phase has ended, the mixture is subsequently
:
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-- 8 --
stirred at 80DC for 4 hours. Thereafter, 15 g o~ 30%
strength H2O2 are added and the mix~ure i5 stirred at 80DC
for a further hour. The colorless 25% strength polymer
solution has an intrinsic viscosity X of between 15 and
20.
Example 4
Preparation of a copolymer of acrylic acid and 25~ of
diallylaminomethylenephosphonic acid
12.5 g o~ diallylamino-methylenephosphonic acid are dis-
solved in a mixture of 100 g of water and 20 g of isopro-
panol and the solution is heaked to 75C, while passing
in a stream of nitrogen. A catalyst solution consisting
of 1.5 g f tNH4)2S2O8 in 30 g of water, and 37.5 g of
acrylic acid are synchronously added dropwise from 2
dropping funnels at this temperature. When the exothermic
reaction phase has ended, the mixture is subsequently
stirred at 80C for 4 hours. The colorless 25% s~rength
polymer solution has an intrinsic viscosity K of between
15 and 20.
Example 5
Preparation of a copolymer of acrylic acid and diallyl-
aminomethylenephosphonic acid using H2O2 as a free radical
chain initiator
The procedure is as described in Example 2, but 4.5 g of
30% strength ~22 in 30 ml of water are used as the cata-
lyst. A 25% strength polymer solution ha~ing an intrinsic
viscosity K of between 15 and 20 is obtained.
Examples 6 and 7
Preparation of copolymers of meth~crylic acid and di-
allylaminomethylenephosphonic acid
The procedure is as described in Example 1, using meth-
acrylic acid and 1% (Example 5) or 10% (Example 6) of
diallylaminomethylenephosphonic acid.
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Example 8
Preparation of a terpolymer of acrylic acid, maleic acid
and diallylaminomethylenephosphonic acid
The procedure is as described in Example 1, using 2.5 g
S of diallylaminomethylenephosphonic acid, ~4 g of acrylic
acid and 24 g of maleic anhydride.
Example 9
Preparation of a terpolymer of acrylic acid, vinyl
acetate and diethyl diallylaminomethylenephosphonate
30 g of acrylic acid, 30 g of vinyl acetate and 6.5 g of
diethyl diallylaminomethylenephosphonate are dissolved
in 174 g of toluene and the solution is heated to 80C,
while passing through a stream of nitrogen. A catalyst
solution of 0.2 g of AIBN in 12 g of toluene is added
from a dropping funnel. When the exothermic reaction
phase has ended, the mixture is allowed to after-react
for 4 hours.
The polymer iB then hydrolyzed by addition of lN NaOH,
the organic solvent being distilled off. A 30% strength
polymer solution having an intrinsic viscosity K of
between 20 and 25 is obtained.
Example 10 (Comparison Example)
Preparation of a copolymer of acrylic acid and diallyl-
aminomethylenephosphonic acid having a high R value
A solution of 10 g of diallylaminomethylenephosphonic
acid in 285 g of water is heated to 40C, while passing
through a stream of nitrogen. A catalyst solution con-
sisting of 3 g of (NX4)S208 in 54 g of water, and 90 g o~
acrylic acid are synchronously added dropwise from 2
dropping funnels at this temperature. After the mixture
has been subsequently stirred at 50C for 5 hours, a 20~
strength polymer solution having an intrinsic viscosity
K of between 130 and 140 is obtained.
The polymerization in this comparison example was carried
out at relatively low temperatures, in accordance with
the information in Japanese Laid-Open Specification
' . : . ' ~:
-- 10 --
50-72,987. However, the polymers thus obtainable show no
action as scale preventers.
Use Examples
1. Barium ~ulfate scale prevanter
5 The scale-preventing action was demonstrated with a tube
plugging test. The principle of this test method com-
prises monitoring the pressure build-up within a thermo-
statically controlled capillary, through which liquid is
flowing, due to the deposition of solids. ~ commercial
apparatus from S.B. Systems, Aberdeen, model PMAC, was
chosen.
For testing for the prevention of barium sulfate
deposits, the following solutions were mixed:
1. Sulfate solu~ion 74.92 g/l of NaCl
0.93 g/l of Na2S0~
2.35 g/l of NaHC03
2. Barium solution 70.09 g/l of NaCl
1.3~ y/l of ~aCl2
1.93 g/l of CaCl2 2H20
3.81 g/l of MgCl2 ~ 6H20
Using a hose pump, the two solutions were mixed continu-
ously and pumped through a stainless steel capillary of
1.1 mm internal diameter. A sensitive pressure sensor
recorded the increase in pressure in the capillary, which
was thermostatically controlled at 70 DC .
A slight increase to about 0.2 bar was awaited, in order
to generate the precipitation of a small amount of barium
sulfate on the steel surface. The inhibitor-free solution
1 was then rapidly replaced by an inhibitor-containing
solution of the same composition. If the pressure
remained constant, successful inhibition of BaS04 pre-
,
" ' '' ' , . ~ ~ ~
cipitation was concluded. If the pressure rose, the
amount of inhibitor or, at the same concentration, the
nature of the inhibitor was inadequate for preventing
scale formation. The minimum concentration of inhibitor
5 which still ~ust prevents the deposition was thus used
to evaluate the effectiveness.
The following graduations were observed by this method incomparative experiments:
Amount of inhibitor (without solvent)
Product 50 ppm 40 ppm 35 ppm 30 ppm 25 ppm
~xample 1 + + + + ~ + + + + + + +
Example 2 ~ + + + + + + + + + ~ +
Example 3 + + + + + + + + + + + +
Example 8 ~ ~ + + + + + * + + + + --
Example 9 + + + .......... ... ... ...
Example 10 ................ ... ... ...
Diallylamino- .................. ... Ø ...
methylenephosphonic acid, homopolymer
~Nalco V936 + + + ... ... ... ...
~Petrolite
SP181 + + ~ ~ ~ + ~ ~ ~ .............. ...
~Petrolite
SP245 + + + + + + + + + .............. ...
The compounds according to the invention thus already
show an action against scale deposits at lower concentra-
tions in comparison with the commercial products from
Petrolite and Nalco which are often employed.
.
2. Calcium carbonate scale preventer
Nhen testing for the prevention of calcium carbonate30 depositP, the following solutions were mixed:
Solution I NaCl 23 g~l
CaC12 x 2H20 2.14 g/l
MgCl2 x 6H20 0.376 g/l
- :: ,
- 12 ~
~Cl 0.84 ~/1
Solution II NaCl 23 g/l
NaHCO3 5 g/l 80C
Using a hose pump, the two solutions were pumped continu-
ously through a mixing cell and ~ stainless steel capil-
lary of 1.1 mm internal diameter. A sensitive pressure
sensor recorded the increase in pressure in the capil-
lary, which was thermostatically controlled at 80C.
An increase to about 0.8 bar was awaited in order to
generate the precipitation of a thin layer of calcium
carbonate on the steel surface. The scale inhibitor was
then added continuously to the mixing cell via a second
pump. If the pressure remained constant, successful
inhibition of CaCO3 precipitation was concluded. If the
pressure rose, the amount of inhibitor or, at the same
concentration, the nature of the inhibitor was inadequate
for preventing scale formation. The minimum concentration
of inhibitor which still ~ust prevents the deposit was
thus used to evaluate the effectivene s.
The following graduations were observed by this method in
comparative experiments
Amount of inhibitor (without solvent)
Product 15 ppm 10 ppm 5 ppm 2 ppm
Example 2 + + + + ~ + ... ...
Example 3 + + + + + + ... ...
Example 4 + + + + + + -~ + + ...
~Bellasol S40 + + + + + + + + + ...
Petrolite
SP237 + + + + + + + + +
~Dodiscale
V2870 + + + + + ~ + ~ +
The polymers according to the invention thus al80 exhibit
an action against C~C03 scale~which is comparable to that
::
.
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- 13 -
of commercial brands often employed (Dodiscale V2870,
Bellasol S40 and P~trolite SP237 are commercial brands of
Hoechst, Ciba-Geigy and Petrolitle respectively).
3. Calcium bonding capacity and calcium dispersion
The dispersion of calcium carbonate was determined by the
filtration method under the following test conditions:
4 mmol of CaCl2, 4.4 mmol of Na2CO3, 2 mmol of NaOH,
250 ppm of polymer, temperature = 40C. The copol~mers
according to Examples 1 and 2 disperse CaCO3 almost
completely, and considerably better than the commercial
product ~Sokalan CP5 (BASF) measured for comparison.
The calcium bonding capacity was mPasured by measurement
of the concentration of free Ca2~ using a Ca-sensitive
electrode in ~0 mmol of NH3/3Q mmol of NH~Cl buffer at a
total concentration of calcium of 2 mmol and calculated
by extrapolation to CpOl~r '
Product Proportion of Ca bonding capacity
CaC03 dispersed [mmol of Catg of
polymer]
Example 1 85 ~ 4.6
Example 2 87 ~ 4.4
~Sokalan CP 5 23 % 5.6
